Akayed Ullah, 27, is being held after an attempted terror attack at America's biggest and busiest bus terminal, officials say. Jeenah Moon for The New York Times

Authorities have identified the suspect responsible for the "terror-related" explosion that occurred during rush hour Monday morning in the subway near New York City's Port Authority and Times Square as 27-year-old Akayed Ullah.

Ullah, who is from Bangladesh and has been in the United States 7 years, was wearing "wearing an improvised low-tech explosive device" that detonated in a subway tunnel in the 42nd Street passageway between 7th and 8th avenues, NYPD commissioner James P. O'Neill told reporters on Monday morning.

While Ullah was badly injured in the arm and torso, he was only person seriously hurt in the explosion, which authorities believed to be an "intentional act." Three people were injured, but none of their wounds appear to be life-threatening, the FDNY said.

In a news conference, Mayor Bill de Blasio called the blast an attempted terrorist attack and said Ullah acted alone, as no other devices had been found.

"This was an attempted terrorist attack," said de Blasio. "Thank God the perpetrator did not achieve his ultimate goals."

"Our lives revolve around the subway," he continued. "The choice of New York is always for a reason, because we are beacons of the world. And we show that a society of many background and many faiths can work."

"The terrorists want to undermine that," he added. "They yearn to attack New York City."

Former NYPD commissioner Bill Bratton said preliminary information indicated that the explosion was carried out in the name of ISIS.

"The preliminary information from three sources, and I emphasize my former word, preliminary, subject to change: It is a man in his middle 20s probably, possibly from Bangladesh. Been in the country about seven years, who was supposedly setting the device off in the name of ISIS. So definitely a terrorist attack, definitely intended," Bratton said on MSNBC.

"As to whether the device malfunctioned or didn't function correctly, that'll have to be determined," Bratton added.

Christina Bathea, 29, told ABC News she was in the passageway on her way to work next to the terminal when she heard a bang, saw smoke and ran.

"If I didn't believe in God, I believe in God today," she said.

On Facebook, evangelist Franklin Graham said the U.S. has once again "has been attacked by radical Islam" and praised President Trump for his controversial travel ban, as the battle is "far from over."

"According to media reports, a Muslim immigrant from Bangladesh, inspired by ISIS, detonated a pipe bomb this morning in New York City. As the Syrian and Iraqi governments celebrate what they call the 'victory over ISIS,' the battle against radical Islam is far from over," he said. "I'm thankful that the Supreme Court agreed with and upheld President Trump's travel ban which is so important for the security of our country...Pray for those injured this morning. Let's also pray for President Donald J. Trump and our leaders in Washington-both Democrat and Republican-that God would give them wisdom and they would listen to His voice."

NBC News notes that the incident comes just six weeks after a truck driver deliberately drove down a bike path in lower Manhattan, killing eight people in the deadliest terror attack in New York City since Sept. 11, 2001.